Intake and exhaust device for vehicle

ABSTRACT

An intake and exhaust device ( 1 ) for a vehicle engine is capable to perform a compression self-ignition operation, the device comprising on an intake passage a supercharger ( 9 ) driven by a force other than an exhaust gas, wherein an exhaust purification device ( 18 ) disposed on an exhaust passage is disposed adjacent to an outer surface of the engine ( 2 ).

TECHNICAL FIELD

The present invention relates to an intake and exhaust device for avehicle, and more specifically relates to an intake and exhaust devicefor a vehicle which includes a supercharger and an exhaust purificationdevice.

BACKGROUND ART

Typically, in a gasoline engine for a vehicle, when gasoline is burnt ata ratio close to a theoretical air fuel ratio, an amount of oxygen leftin an exhaust gas, generated by the burning, becomes small. However, ina case where a gasoline particulate filter (GPF) for purifying anexhaust gas is provided downstream of the engine, oxygen is required forpurifying the exhaust gas in the GPF, and hence the entire exhaust gasmay not be purified in the GPF when the amount of oxygen in the exhaustgas is small. Therefore, for example as in the case of an enginedescribed in Patent Document 1, it is conceivable that a turbo chargeris provided for supercharging so as to perform lean-burn.

CITATION LIST Patent Document

Patent Document 1: Japanese Patent Laid-Open No. 2012-57519

SUMMARY OF INVENTION Technical Problem

Meanwhile, for example, when an operation with favorable heat efficiencyis performed by a compression self-ignition operation, the temperatureof the exhaust gas may become relatively low. In a catalyst which isprovided downstream of the engine for purification of the exhaust gas,an activation temperature range needs to be set in advance, but therange for the activation temperature, to which the catalyst needs tocorrespond, becomes wide when the temperature of the exhaust gas may below, thus making it difficult to set the activation temperature range.Especially in the case of an engine using both the compressionself-ignition operation and a spark ignition operation, since atemperature range for a possible exhaust gas becomes wide, for example,when the activation temperature range for the catalyst is set to be onthe high temperature side, the catalyst becomes less likely tocorrespond to the exhaust gas with a low temperature at the time of thecompression self-ignition operation.

It is an object of the present invention to provide an intake andexhaust device for a vehicle engine which is capable of ensuring anactivation environment for a catalyst of an exhaust purification devicewhile ensuring favorable burning and operation in an engine capable ofconducting a compression self-ignition operation.

Solution to Problem

For achieving the above object, an intake and exhaust device for avehicle engine of the present invention is an intake and exhaust devicefor a vehicle engine which is capable to perform a compressionself-ignition operation, the device including on an intake passage asupercharger driven by a force other than an exhaust gas, and an exhaustpurification device disposed on an exhaust passage is disposed adjacentto an outer surface of the engine.

In the present invention as thus configured, since the intake andexhaust device for the vehicle engine includes the supercharger, anamount of air required for compression self-ignition is ensured, and anintake flow in a furnace increases to accelerate the burning. As aresult, generation of a deposit is suppressed.

The exhaust purification device is adjacent to the outer surface of theengine and is thereby disposed near the engine. Hence an exhaust gasdischarged from the engine passes through a shorter path and isinstantly introduced into the exhaust purification device, therefore, adecrease in temperature of the exhaust gas is reduced and the exhaustgas with a relatively high temperature is introduced into the exhaustpurification device. Therefore, for example, even when an exhaust gas,generated in the case of burning by compression self-ignition, has arelatively low temperature, the supply of the exhaust gas in excessivelylow temperature to the exhaust purification device is avoided,therefore, the exhaust gas is favorably purified by the catalyst and thelike of the exhaust purification device. Further, the aboveconfiguration facilitates the setting of the activation temperaturerange for the catalyst even when, for example, the catalyst is in usefor the exhaust purification device in the vehicle engine using both thecompression self-ignition operation and the spark ignition operation.

With the supercharger being driven by a force other than the exhaustgas, the supercharger is prevented from taking energy out of the exhaustgas. This prevents a decrease in temperature before the exhaust gasreaches the exhaust purification device, and also thereby, an exhaustgas with a relatively high temperature is supplied to the exhaustpurification device, thus leading to favorable purification of theexhaust gas.

In the present invention, the supercharger is preferably a “supercharger(mechanical supercharger)” driven by an output shaft of the engine, oran electric supercharger.

In the present invention as thus configured, since the supercharger isthe “supercharger” driven by the output shaft of the engine or is theelectric supercharger, the supercharger is prevented from taking theenergy out of the exhaust gas as compared to the case of using asupercharger driven by a force of an exhaust gas, such as a turbocharger. This prevents a decrease in temperature of the exhaust gasbefore the exhaust gas reaches the exhaust purification device, whichenables the supply of an exhaust gas with a relatively high temperatureto the exhaust purification device, thus leading to favorablepurification of the exhaust gas.

In the present invention, it is preferable that the intake and exhaustdevice is capable to perform a spark ignition operation, a turbosupercharger is provided upstream of the exhaust purification device onthe exhaust passage, supercharging is performed by the turbosupercharger when the spark ignition operation is conducted, andsupercharging be performed by the “supercharger” when the compressionself-ignition operation is conducted.

In the present invention as thus configured, since it is configured suchthat the supercharging is performed by the turbo supercharger when thespark ignition operation is conducted, and the supercharging isperformed by the “supercharger” when the compression self-ignitionoperation is conducted, at the time of the compression self-ignitionoperation, the temperature of the exhaust gas is prevented fromdeviating from the activation temperature range for a catalyst device,and at the time of spark ignition operation, especially at the time of ahigh-load operation, the energy of the exhaust gas is consumed by thedrive of the turbo supercharger to prevent the temperature of theexhaust gas from deviating from the activation temperature range for thecatalyst device.

In the present invention, it is preferable that the intake and exhaustdevice is capable to perform a spark ignition operation, a turbosupercharger is provided upstream of the exhaust purification device onthe exhaust passage, supercharging is performed by the turbosupercharger when the spark ignition operation is conducted, andsupercharging is performed by the electric supercharger when thecompression self-ignition operation is conducted.

In the present invention as thus configured, since it is configured suchthat the supercharging is performed by the turbo supercharger when thespark ignition operation is conducted and the supercharging is performedby the electric supercharger when the compression self-ignitionoperation is conducted, at the time of the compression self-ignitionoperation, the temperature of the exhaust gas is prevented fromdeviating from the activation temperature range for a catalyst device,and at the time of spark ignition operation, especially at the time of ahigh-load operation, the energy of the exhaust gas is consumed by thedrive of the turbo supercharger to prevent the temperature of theexhaust gas from deviating from the activation temperature range for thecatalyst device.

In the present invention, it is preferable that the engine have anintake system disposed on a vehicle-front side and an exhaust systemdisposed on a vehicle-rear side, and the supercharger is disposed on thevehicle-front side of the engine.

In the present invention as thus configured, since the exhaust system isdisposed on the vehicle-rear side of the engine, the exhaustpurification device of the exhaust system is hidden by the engine whenthe vehicle travels, to prevent the exhaust purification device frombeing overcooled by the wind generated by traveling. This ensures afavorable activation environment for the catalyst of the exhaustpurification device.

Further, since the intake system is disposed on the vehicle-front sideof the engine and the supercharger is also disposed on the vehicle-frontside, the intake system including the supercharger is collectivelydisposed on the vehicle-front side of the engine, thus leading toimprovement in response to the supercharging.

In the present invention, it is preferable that the exhaust purificationdevice includes a particulate filter part and an exhaust gasrecirculation (EGR) gas leading part provided downstream of theparticulate filter part, and the EGR gas leading part is connected to anupstream of the supercharger via an EGR gas passage.

In the present invention as thus configured, in the exhaust purificationdevice, since the EGR gas leading part is provided downstream of theparticulate filter part and the EGR gas leading part is connected to theupstream of the supercharger, an exhaust gas with its deposit reduced bythe particulate filter part is supplied to the upstream of thesupercharger, thereby suppressing adhesion of the deposit component tothe inside of the supercharger, to suppress deterioration insupercharging efficiency.

In the present invention, it is preferable that the exhaust purificationdevice is supported on the outer surface of the engine by a supportpart, and a weight part of the exhaust purification device is disposedextending in a direction away from the outer surface than the supportpart.

According to the present invention with such a configuration, theexhaust purification device is supported on the outer surface of theengine by the support part, and the weight part of the exhaustpurification device is disposed extending in the direction away from theouter surface of the engine than the support part, therefore, theexhaust purification device vibrates to function as a dynamic damperduring the operation of the engine. As a result, the vibration of theexhaust purification device reduces the vibration of the engine, whichleads to reduction in vibration and noise of the vehicle.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view of an intake and exhaust device for a vehicleaccording to a first embodiment of the present invention.

FIG. 2 is a side view of the intake and exhaust device for the vehicleaccording to the first embodiment of the present invention.

FIG. 3 is a side view of the intake and exhaust device for the vehicleaccording to the first embodiment of the present invention, with a partof the device broken.

FIG. 4 is a bottom view of the intake and exhaust device for the vehicleaccording to the first embodiment of the present invention.

FIG. 5 is a perspective view of the intake and exhaust device for thevehicle according to the first embodiment of the present invention.

FIG. 6 is an enlarged perspective view showing a part of an exhaustsystem device of the vehicle according to the first embodiment of thepresent invention.

FIG. 7 is a side view of an intake and exhaust device for a vehicleaccording to a second embodiment of the present invention.

FIG. 8 is a plan view of an intake and exhaust device for a vehicleaccording to a third embodiment of the present invention.

FIG. 9 is a partial enlarged perspective view showing an installationstructure of an exhaust purification device according to a thirdembodiment of the present invention.

FIG. 10 is a side view of an intake and exhaust device for a vehicleengine according to the third embodiment of the present invention.

FIG. 11 is a partial enlarged sectional view showing an installationstructure of an exhaust purification device according to the thirdembodiment of the present invention.

FIG. 12 is a side view showing the installation structure of the exhaustpurification device according to the third embodiment of the presentinvention.

FIG. 13 is a bottom view showing the installation structure of theexhaust purification device according to the third embodiment of thepresent invention.

DESCRIPTION OF EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed below with reference to the accompanying drawings. In a secondembodiment and thereafter, similar constituents to in the firstembodiment are provided with the same numerals as in the firstembodiment and the description thereof will be simplified or omitted.

First Embodiment

FIG. 1 shows a plan view of an intake and exhaust device 1 for a vehicleaccording to a first embodiment of the present invention, FIG. 2 shows aside view of the intake and exhaust device 1 for the vehicle accordingto the first embodiment of the present invention, FIG. 3 shows a sideview of the intake and exhaust device 1 for the vehicle according to thefirst embodiment of the present invention, with a part of the devicebroken, and FIG. 4 shows a bottom view of the intake and exhaust device1 for the vehicle according to the first embodiment of the presentinvention. FIG. 1 is a view of the intake and intake and exhaust device1 for the vehicle viewed from above, and in this figure, the horizontaldirection indicates the longitudinal direction of the vehicle, the leftside indicates the front direction of the vehicle, and the right sideindicates the rear direction of the vehicle. Further, in this figure,the vertical direction indicates the vehicle-width direction of thevehicle, the upper side indicates the right direction of the vehicle,and the lower side indicates the left direction of the vehicle.

As shown in these FIGS. 1 to 4, the intake and exhaust device 1 for thevehicle according to the first embodiment of the present invention isapplied to an engine 2 of a compression self-ignition system, such as adiesel engine or a homogeneous-charge compression ignition (HCCI)gasoline engine. The engine 2 includes a cylinder block 4 and a cylinderhead 6 fitted to the upper portion of the cylinder block 4. In thepresent embodiment, inside an engine room 102, the engine 2 is disposedsuch that a crank shaft (not shown) is disposed along a vehicle-widthdirection of a vehicle 100, an intake system is disposed on thevehicle-front side of the engine 2, and an exhaust system is disposed onthe vehicle-rear side of the engine 2, therefore, the engine 2 is thus aso-called front-intake rear-exhaust engine.

An intake manifold 8 integrated with a water-cooling inter cooler isfitted to the intake side of the engine 2, and a supercharger(mechanical supercharger) 9 is connected to the upstream side of theintake manifold 8 above the intake manifold 8, the supercharger 9extending along the direction of the crank shaft of the engine 2,namely, along the vehicle-width direction of the vehicle 100 in thepresent embodiment. An EGR valve 10 is provided upstream of thesupercharger 9. The EGR valve 10 is located to the left side of thecenter of the engine 2 in the vehicle-width direction, and morespecifically, the EGR valve 10 is located at substantially the sameposition as the left-side side surface of the engine 2 in thevehicle-width direction. A pipe provided with the EGR valve 10, thesupercharger 9, and a passage for intake which passes through the intakemanifold 8 constitute an intake passage 11 in the present embodiment. Inthe present embodiment, the supercharger 9 is a supercharger of a systemto obtain a driving force from the output shaft of the engine 2 via abelt.

FIG. 5 is a perspective view of the intake and exhaust device 1 for thevehicle according to the first embodiment of the present invention. Asshown in this FIG. 5 and aforementioned FIGS. 1 to 4, an exhaustmanifold 12 is fitted to the discharge side of the engine 2. The exhaustmanifold 12 includes a plurality of discharge pipes 14 connected toexhaust ports (not shown) for respective cylinders (four cylinders inthe present embodiment) of the engine 2, and a mixing tube 16 whereexhaust gases passing through the discharge pipes 14 converge. Thedischarge pipes 14 respectively extend from the exhaust ports of thecylinder block 4 toward the rear side of the vehicle 100, extend whilebeing bent to the right in the vehicle-width direction on the downstreamthereof, and are connected to the mixing tube 16 on the right side ofthe exhaust manifold 12 while sequentially converging with the adjacentdischarge pipes 14 on substantially the same horizontal planes. Withsuch a structure, when the exhaust manifold 12 is viewed from above, themixing tube 16 is disposed on the right side of the exhaust manifold 12in the vehicle-width direction and also disposed to the right of thecenter of the engine 2 in the vehicle-width direction. The mixing tube16 is open on the lower surface while vertically extending in a shortdistance. An exhaust system device 1A of the present embodiment isconnected to the mixing tube 16 via an exhaust purification deviceintroduction passage 17.

The exhaust purification device introduction passage 17 has a gas inlet17A and a gas outlet 17B. The gas inlet 17A is open upward and iscoupled to an opening of the mixing tube 16. The gas outlet 17B is openin a direction substantially orthogonal to the gas inlet 17A, andspecifically, the gas outlet 17B is open to the left in thevehicle-width direction.

The exhaust system device 1A includes: an exhaust purification device 18for purifying an exhaust gas received from the exhaust manifold 12; aflexible pipe 20 connected to the exhaust purification device 18 so asto discharge the exhaust gas passing through the exhaust purificationdevice 18 to the outside; an EGR gas leading part 22 for taking out apart of the exhaust gas passing through the exhaust purification device18 as an EGR gas; a first EGR cooler 24 and a second EGR cooler 26connected to the EGR gas leading part 22 and for cooling the EGR gastaken out of the exhaust purification device 18; a first EGR pipe 28coupling the first EGR cooler 24 and the second EGR cooler 26; and asecond EGR pipe 30 coupling the second EGR cooler 26 and the intakepassage 11.

The exhaust purification device 18 has a substantially L-shape as viewedfrom the above of the vehicle 100 and includes an upstream-side portion32 connected to the mixing tube 16 of the exhaust manifold 12 and adownstream-side portion 34 provided downstream of the upstream-sideportion 32 and connected to the flexible pipe 20 and the EGR gas leadingpart 22.

The upstream-side portion 32 is a substantially cylindrical portioncoupled to the gas outlet 17B of the exhaust purification deviceintroduction passage 17 and is disposed with its central axis(longitudinal axis) along the vehicle-width direction. Hence the outersurface of the upstream-side portion 32 is disposed adjacent to theouter surface of the cylinder block 4 of the engine 2. A catalyst deviceis incorporated in the upstream-side portion 32.

The downstream-side portion 34 is a substantially cylindrical portionintegrally formed in the upstream-side portion 32 and is disposed withits central axis (longitudinal axis) substantially at the right angle tothe central axis of the upstream-side portion 32. Further, the centralaxis of the downstream-side portion 34 extends in the longitudinaldirection of the vehicle 100, and is disposed such that the upstream endof the downstream-side portion 34 is located above the downstream end,namely, such that the central axis is inclined downwardly from theupstream end to the downstream end of the downstream-side portion 34. Agasoline particulate filter (GPF) is incorporated in the downstream-sideportion 34.

With such a structure, the upstream-side portion 32 of the exhaustpurification device 18 is disposed along the vehicle-width directionbelow the exhaust manifold 12, and the downstream-side portion 34 isdisposed along the longitudinal direction of the vehicle 100 on the leftto the center of the engine 2 in the vehicle-width direction.

The flexible pipe 20 is a cylindrical member connected to an exhaustoutlet 18A formed at the downstream end of the downstream-side portion34 of the exhaust purification device 18 and is formed of a materialextendable and retractable or bendable to a certain extent. The flexiblepipe 20 is coupled to the exhaust outlet 18A disposed on the right sidein the vehicle-width direction and the lower side in the verticaldirection on the circular end surface 18B at the downstream end of thedownstream-side portion 34 of the exhaust purification device 18.Further, the central axis (longitudinal axis) of the flexible pipe 20extends in the longitudinal direction of the vehicle 100 and is disposedsuch that the downstream-side end is located below the upstream-sideend, namely, such that the central axis is inclined downwardly from theupstream-side end to the downstream-side end, and an inclined angle ofthe central axis is set to be larger than an inclined angle of thedownstream-side portion 34 of the exhaust purification device 18.

FIG. 6 is an enlarged perspective view showing a part of the exhaustsystem device 1A for the vehicle according to the first embodiment ofthe present invention. As shown in this FIG. 6 and aforementioned FIGS.1 to 5, the EGR gas leading part 22 is a tubular member coupled to anEGR gas outlet 18C formed at the downstream end of the downstream-sideportion 34 of the exhaust purification device 18. The EGR gas leadingpart 22 is coupled to the EGR gas outlet 18C disposed at a position onthe left side in the vehicle-width direction and the upper side in thevertical direction on the circular end surface 18B at the downstream endof the downstream-side portion 34. With such a placement, a connectionpart between the EGR gas leading part 22 and the exhaust purificationdevice 18 is located above a connection part between the flexible pipe20 and the exhaust purification device 18 and on the left thereto in thevehicle-width direction.

The longitudinal axis of the EGR gas leading part 22 is disposed alongthe longitudinal direction of the vehicle 100, namely, along a gas flowdirection of an exhaust gas flowing through the downstream-side portion34 and substantially parallel to the central axis of the downstream-sideportion 34, and the upstream end 22A of the EGR gas leading part 22 isopen to the surface intersecting with the axis parallel to the centralaxis of the downstream-side portion 34, which is the surfacesubstantially orthogonal to the central axis of the downstream-sideportion 34 in the present embodiment.

The EGR gas leading part 22 is formed in a substantially rectangularcross-section shape and tapered toward the downstream. Specifically, theEGR gas leading part 22 has a right side surface 22B, an upper surface22C, a lower surface 22D, a left side surface 22E, and a downstream endsurface 22F, the right side surface 22B is an inclined surface inclinedto the left in the vehicle-width direction toward the downstream, theupper surface 22C is an inclined surface inclined downwardly toward thedownstream and the lower surface 22D is an inclined surface inclinedupward as going downstream. However, the left side surface 22E has aflat surface parallel to the central axis of the downstream-side portion34. Further, the downstream end surface 22F has a flat surfacesubstantially orthogonal to the central axis of the downstream-sideportion 34 of the exhaust purification device 18.

A downstream end 22G of the EGR gas leading part 22 is formed on theleft side surface 22E, and hence an outlet (downstream end 22G) of theEGR gas leading part 22 is open to the left in the vehicle-widthdirection. The surface of the outlet of the EGR gas leading part 22,including the opening surface, is disposed so as to be in contact withthe circumference of the downstream-side portion 34.

The first EGR cooler 24 is a water-cooling type EGR cooler and includesa first EGR cooler body 36, a first EGR gas flow-in part 38 formed atone upstream end of the first EGR cooler body 36, and a first EGR gasflow-out part 40 formed at the other downstream end of the first EGRcooler body 36.

The first EGR cooler body 36 is formed in a substantially rectangularparallelepiped, a longitudinal axis of the first EGR cooler body 36 isdisposed substantially parallel to the central axis of thedownstream-side portion 34 of the exhaust purification device 18, andone side surface of the first EGR cooler body 36 is disposed adjacent tothe circumferential surface of the downstream-side portion 34.

A bracket 42 projecting from the side surface of the first EGR coolerbody 36 toward the exhaust purification device 18 is provided on theupper surface of the first EGR cooler body 36, and by fixing thisbracket 42 to the side surface of the downstream-side portion 34 of theexhaust purification device 18 by bolting, welding, or the like, theouter surface of the first EGR cooler 24 is fixed to the outer surfaceof the exhaust purification device 18. Hence the first EGR cooler 24 andthe exhaust purification device 18 are fixed and fitted to each other ina place different from where the first EGR cooler 24 is connected to theexhaust purification device 18 via the EGR gas leading part 22.

The first EGR gas flow-in part 38 is located behind the first EGR coolerbody 36 in the vehicle, is formed in a tubular shape, and is coupledintegrally to the first EGR cooler body 36 at one end 38A on the firstEGR cooler body 36 side. The other end of the first EGR gas flow-in part38 is open to the right in the vehicle-width direction, namely, to thesurface substantially orthogonal to the vehicle-width direction, tobecome a first EGR gas flow inlet 38B of the first EGR cooler 24. Thefirst EGR gas flow inlet 38B is coupled to an outlet (downstream end22G) of the EGR gas leading part 22, whereby the first EGR cooler 24communicates with the EGR gas leading part 22. On a left side surface38C of the first EGR gas flow-in part 38 in the vehicle-width direction,an inclined surface is formed which is inclined to the right toward therear of the vehicle 100, namely, inclined to the gas flow inlet 38B (EGRgas leading part 22) side as going upstream of the first EGR gas flow-inpart 38.

As thus described, the upstream end 22A of the EGR gas leading part 22is open to the direction of the exhaust purification device 18 along thelongitudinal direction of the vehicle 100, the downstream end 22G of theEGR gas leading part 22 is open to the left in the vehicle-widthdirection, the first EGR gas flow inlet 38A of the first EGR cooler 24is open to the right, and the one end 38A is open to the direction alongthe longitudinal direction of the vehicle 100, whereby the direction ofthe path of the EGR gas leading from the EGR gas outlet 18A of theexhaust purification device 18 to the upstream end of the first EGRcooler body 36 is changed from the rear of the vehicle 100 to the leftin the vehicle-width direction at the EGR gas leading part 22 and isthen changed to the front at the first EGR gas flow-in part 38, and as awhole, the direction is rotated from the rear to the front by 180°.Further, the first EGR cooler 24 is disposed on the left to thedownstream-side portion 34 of the exhaust purification device 18 in thevehicle-width direction, and whereby, the first EGR cooler 24 isadjacent to the side surface of the exhaust purification device 18 onthe EGR valve 10 side of the intake passage 11 with respect to thevehicle-width direction.

The first EGR gas flow-out part 40 is located in front of the first EGRcooler body 36 in the vehicle, is formed in a tubular shape, and iscoupled integrally to the first EGR cooler body 36 at one end 40A on thefirst EGR cooler body 36 side. The other end of the first EGR gasflow-out part 40 is open to the left in the vehicle-width direction,namely, to the surface substantially orthogonal to the vehicle-widthdirection, to become a first EGR gas flow outlet 40B of the first EGRcooler 24. The first EGR gas flow outlet 40B is coupled to one end ofthe first EGR pipe 28. On a right-side surface 40C of the first EGR gasflow-out part 40 in the vehicle-width direction, an inclined surface isformed which is inclined to the left toward the front of the vehicle100, namely, inclined to the first EGR gas flow outlet 40B (first EGRpipe 28) side as going downstream of the first EGR gas flow-out part 40.

The first EGR cooler 24 with such a structure as described above isdisposed as inclined downwardly toward the upstream side, namely,inclined downwardly toward the rear of the vehicle. Hence the first EGRgas flow outlet 40B of the first EGR cooler 24 is located above thefirst EGR gas flow inlet 38B. The inclined angle of the first EGR cooler24 is larger than the inclined angle of the downstream-side portion 34of the exhaust purification device 18 and is substantially the same asthe inclined angle of the flexible pipe 20.

Further, in the side view, the first EGR cooler 24 is accommodatedwithin a vertical dimension of the downstream-side portion 34 of theexhaust purification device 18, and in the side view, the first EGRcooler 24 does not project upward or downward from the exhaustpurification device 18.

The second EGR cooler 26 is a water-cooling type EGR cooler, andincludes a second EGR cooler body 46, a second EGR gas flow-in part 48formed at one end of the second EGR cooler body 46 on the upstream side,and a second EGR gas flow-out part 50 formed at the other end of thesecond EGR cooler body 46 on the downstream side.

The second EGR cooler body 46 is formed in a substantially rectangularparallelepiped, a longitudinal axis of the second EGR cooler body 46 isdisposed along the longitudinal direction of the vehicle 100, and oneside surface of the second EGR cooler body 46 is disposed adjacent tothe left surface of the cylinder block 4 of the engine 2.

Further, a bracket 52 projecting upward from the upper surface of thesecond EGR cooler body 46 or projecting downward from the lower surfacethereof is provided on each of the upper surface and the lower surfaceof the second EGR cooler body 46, and by fixing this bracket 52 to theleft side surface of the cylinder block 4 by bolting, welding, or thelike, the outer surface of the second EGR cooler 26 is fixed and fittedto the outer surface of the cylinder block 4.

The second EGR gas flow-in part 48 is located behind the second EGRcooler body 46 in the vehicle, is formed in a tubular shape, and iscoupled integrally to the second EGR cooler body 46 at one end 48A onthe second EGR cooler body 46 side. The other end of the second EGR gasflow-in part 48 is open to the rear of the vehicle 100, to become asecond EGR gas flow inlet 48B of the second EGR cooler 26. The secondEGR gas flow inlet 48B is coupled to the other end of the first EGR pipe28.

The second EGR gas flow-out part 50 is located in front of the secondEGR cooler body 46 in the vehicle, is formed in a tubular shape, and iscoupled integrally to the second EGR cooler body 46 at one end 50A onthe second EGR cooler body 46 side. The other end of the second EGR gasflow-out part 50 is open to the front of the vehicle 100, to become asecond EGR gas flow outlet 50B of the second EGR cooler 26. The secondEGR gas flow outlet 50B is coupled to one end of the second EGR pipe 30.

The second EGR cooler 26 with such a structure as described above isdisposed as inclined downwardly toward the upstream side, namely,inclined downwardly toward the rear of the vehicle. Hence the second EGRgas flow inlet 48B is disposed vertically below the second EGR gas flowoutlet 50B in the vehicle vertical direction. The inclined angle of thesecond EGR cooler 26 is smaller than the inclined angle of thedownstream-side portion 34 of the exhaust purification device 18.Further, the second EGR gas flow inlet 48B is disposed above the firstEGR gas flow outlet 40B of the first EGR cooler 24 and on the leftthereto in the vehicle-width direction. With such a placement, thesecond EGR cooler 26 is located above the exhaust purification device 18and the first EGR cooler 24 and on the left thereto in the vehicle-widthdirection.

Note that the first EGR cooler 24 and the second EGR cooler 26 are thewater-cooling types and are thus provided with cooling water inlets 24A,26A and cooling water outlets 24B, 26B, respectively. The cooling wateroutlet 24B of the first EGR cooler 24 communicates with the coolingwater inlet 26A of the second EGR cooler 26, and hence cooling-watercircuits of the first EGR cooler 24 and the second EGR cooler 26 arecoupled in series. Cooling water passing through the first EGR cooler 24and the second EGR cooler 26 and come out of the cooling water outlet26B cools each part of the engines, such as the cylinder head and thecylinder block wall surface, while being cooled by a radiator as needed,and returns to the cooling-water inlet 24A of the first EGR cooler 24.

The first EGR pipe 28 is a tubular member communicating the first EGRgas flow-out part 40 of the first EGR cooler 24 with the second EGR gasflow-in part 48 of the second EGR cooler 26 and is formed of a rubberhose in the present embodiment. The first EGR pipe 28 is coupled to thefirst EGR gas flow-out part 40 along the vehicle-width direction,extends while being bent upward and to the front of the vehicle 100, andis coupled to the second EGR gas flow-in part 48 along the direction tothe front of the vehicle 100.

The second EGR pipe 30 is a tubular member communicating the second EGRgas flow-out part 50 of the second EGR cooler 26 with the intake passage11. The second EGR pipe 30 extends along the direction to the front ofthe vehicle 100, extends while being bent upward on the lower side ofthe intake passage 11, and is coupled to the EGR valve 10 from below.

In the present embodiment, there is formed an EGR gas passage includingthe first EGR cooler 24, the second EGR cooler 26, the first EGR pipe28, and the second EGR pipe 30, for supplying a part of an exhaust gas,taken out of the exhaust purification device 18, to the intake side asan EGR gas.

Here, the placement of the exhaust system device 1A with respect to thevehicle 100 will be described.

As shown in FIGS. 2 to 4, the engine 2 and the exhaust system device 1Aare disposed in the engine room 102 of the vehicle 100, and a vehicleinterior 104 is formed behind the engine room 102. The engine room 102and the vehicle interior 104 are partitioned by a dash panel 106. Thedash panel 106 includes a lower dash panel 108 disposed in a lower partof the vehicle interior 104, and an upper lower dash panel 110 coupledto the front end of the lower dash panel 108 and extending to the frontpart of the vehicle interior 104 in the vehicle-width direction.

A floor tunnel 112 extending in the longitudinal direction of thevehicle 100 and projecting to the vehicle interior 104 side is formed inthe lower dash panel 108 and the upper lower dash panel 110. A floortunnel region 114 is a lower-side region of the floor tunnel 112, whichis surrounded by a projecting portion of the floor tunnel 112 and opendownward and includes in its front-end portion a tunnel extension region116 having cross-sectional area which increases toward the front of thevehicle 100. In the tunnel extension region 116, as shown in FIGS. 1 and4, the width of the floor tunnel region 114 in the vehicle-widthdirection gradually increases as viewed from the vertical direction ofthe vehicle 100, and this increase in the width stops at a front end110A projecting to the frontmost end side of the upper lower dash panel110 on each side of the floor tunnel region 114 in the vehicle-widthdirection. Therefore, in the present embodiment, the front end of thetunnel extension region 116 is located on a vertical plane P passingthrough the front end 110A of the upper lower dash panel 110. As thusdescribed, the tunnel extension region 116 means a region to a positionwhere the width of the floor tunnel region 114 in the vehicle-widthdirection stops increasing, and the floor tunnel region 114 includes thetunnel extension region 116.

Moreover, as shown in FIGS. 2 and 3, in the side view of the vehicle100, the upper surface and the lower surface of the floor tunnel region114 are inclined upwardly toward the front. FIGS. 2 and 3 also show theplane P being the front end of the tunnel extension region 116. In theside view of the vehicle 100, a position Q where the plane P at thefront end of the tunnel extension region 116 intersects with a line Lextending from the upper end of the floor tunnel 112 is the upper end ofthe tunnel extension region 116. Further, as viewed from the front ofthe vehicle 100, the border of the tunnel extension region 116 in thevehicle-width direction is located at the front end 110A of the upperlower dash panel 110.

In the exhaust system device 1A for the vehicle of the presentembodiment, the center of the engine 2 in the width direction is locatedto the right of the center of the floor tunnel region 114 in the widthdirection. The exhaust purification device 18, the flexible pipe 20, theEGR gas leading part 22, the first EGR cooler 24, and the second EGRcooler 26 are disposed at positions overlapping the floor tunnel region114, as viewed from the front of the vehicle 100. The exhaustpurification device 18, a part of the flexible pipe 20, the EGR gasleading part 22, and the first EGR cooler 24 are also disposed atpositions overlapping a region other than the tunnel extension region116 in the floor tunnel region 114, as viewed from the front of thevehicle 100.

Moreover, as shown in FIGS. 1 to 4, the vehicle-rear-side portions ofthe exhaust purification device 18 and the first EGR cooler 24 aredisposed within the floor tunnel region 114. More specifically, a partof the downstream-side end of the exhaust purification device 18, mostof the EGR gas leading part 22, most of the first EGR gas flow-in part38 of the first EGR cooler 24, and most of the flexible pipe 20 aredisposed within the tunnel extension region 116 which is thevehicle-front-side end of the floor tunnel region 114. Therefore, thedownstream-side end of the exhaust purification device 18, the EGR gasleading part 22, the first EGR gas flow-in part 38, and the flexiblepipe 20 are disposed so as to overlap the floor tunnel region 114 asviewed from the vertical direction and the lateral side of the vehicle100.

The exhaust system device 1A for the vehicle with such a structure actsas follows.

First, an exhaust gas discharged from the engine 2 passes through thedischarge pipe 14 of the exhaust manifold 12, merges into the mixingtube 16, flows downward, and flows into the exhaust purification deviceintroduction passage 17. The exhaust gas flown into the exhaustpurification device introduction passage 17 changes its direction fromthe below to the left in the vehicle-width direction and enters theexhaust purification device 18. In the exhaust purification device 18,the exhaust gas passes to the left through the catalyst device of theupstream-side portion 32, passes to the rear of the vehicle 100 throughthe GPF of the downstream-side portion 34, and is purified. A part ofthe exhaust gas after the passage through the downstream-side portion 34comes out of the exhaust outlet 18A, passes through the flexible pipe20, and is then discharged out of the vehicle through a muffler or thelike (not shown).

Meanwhile, the remaining part of the exhaust gas after the passagethrough the downstream-side portion 34 flows as the EGR gas from the EGRgas outlet 18C into the EGR gas leading part 22 toward the rear of thevehicle 100. The EGR gas changes the gas flow direction to the left inthe vehicle-width direction while being guided to the right side surface22B, the upper surface 22C, and the lower surface 22D of the EGR gasleading part 22, and changes the gas flow direction to the front whilebeing guided to the left side surface 38C of the first EGR gas flow-inpart 38 of the first EGR cooler 24, to rotate the gas flow direction by180°.

The EGR gas flowing toward the front of the vehicle 100 enters the firstEGR cooler body 36 from the first EGR gas flow-in part 38 to be cooledand comes out of the first EGR gas flow-out part 40 into first EGR pipe28 while changing the gas flow to the left in the vehicle-widthdirection. The EGR gas passing through the first EGR pipe 28 flows intothe second EGR cooler 26 toward the front of the vehicle 100, is furthercooled by the second EGR cooler 26, enters the second EGR pipe 30 fromthe second EGR cooler 26 toward the front of the vehicle 100, and flowsinto the intake passage 11 via the EGR valve 10.

The exhaust system device 1A for the vehicle with such a structureachieves effects as described below.

Since the supercharger 9 is provided in the intake and exhaust device 1of the engine 2, the lean-burn can be performed to leave oxygen requiredfor the GPF of the exhaust purification device 18 in the exhaust gas,and hence the exhaust gas is favorably purified in the GPF. Further, bythe supercharger 9 performing the supercharging, it is possible toensure an amount of air required for the compression self-ignition.Moreover, the intake flow in the furnace increases due to thesupercharging, thereby enabling acceleration of burning. It is thuspossible to suppress generation of a deposit.

The exhaust purification device 18 is adjacent to the outer surface ofthe engine 2 and therefore, disposed near the engine 2. Hence theexhaust gas discharged from the engine 2 passes through a shorter pathand is instantly introduced into the exhaust purification device 18,therefore, the temperature of the exhaust gas is less likely to decreaseand the exhaust gas with a relatively high temperature can be introducedinto the exhaust purification device 18. Therefore, even when an exhaustgas which is generated in the case of burning by compressionself-ignition has a relatively low temperature, it is possible to avoidintroduction of the exhaust gas in excessively low temperature into theexhaust purification device 18, and it is thus possible to favorablypurify the exhaust gas in the catalyst device of the exhaustpurification device 18.

For example, in the vehicle engine using both the compressionself-ignition operation and the spark ignition operation, it wasconventionally difficult to set the activation temperature range for thecatalyst device of the exhaust purification device 18 due to a widetemperature range conceivable for the exhaust gas. In the presentembodiment, the exhaust purification device 18 is disposed adjacent tothe outer surface of the engine 2, therefore, it is possible to reducethe decrease in temperature of the exhaust gas and prevent thetemperature of the exhaust gas from deviating from the activationtemperature range for the catalyst device. This facilitates the settingof the activation temperature range for the catalyst device.

Since the supercharger 9 is driven by the force of burning of the engine2, it is possible to prevent the supercharger from taking the energy outof the exhaust gas as compared to the case of using a superchargerdriven by the force of the exhaust gas, such as a turbo charger. It isthus possible to prevent the decrease in temperature of the exhaust gasbefore the exhaust gas reaches the exhaust purification device 18, whichalso enables the supply of an exhaust gas with a relatively hightemperature to the exhaust purification device 18, leading to favorablepurification of the exhaust gas.

Since the exhaust system device 1A is disposed on the vehicle-rear sideof the engine 2, the exhaust purification device 18 of the exhaustsystem device 1A is hidden behind the engine 2 when the vehicle 100travels, and it is thus possible to prevent the exhaust purificationdevice 18 from being overcooled by the wind generated by traveling.Hence a favorable activation environment for the catalyst device of theexhaust purification device 18 can be ensured.

Further, with the intake system device being disposed on thevehicle-front side of the engine 2 and the supercharger 9 being alsodisposed on the vehicle-front side, the intake system device includingthe supercharger 9 is collectively disposed on the vehicle-front side ofthe engine 2. This can lead to improvement in response to thesupercharging.

Since the EGR gas leading part 22 is disposed downstream of the GPF ofthe exhaust purification device 18 and the EGR gas leading part 22 isconnected to the upstream of the supercharger 9 via the EGR gas passageincluding the first and second EGR coolers 24, 26 and the first andsecond EGR pipes 28, 30, an exhaust gas with its deposit reduced by theGPF can be supplied to the upstream of the supercharger 9, therebysuppressing adhesion of the deposit component to the inside of thesupercharger 9. It is thereby possible to suppress deterioration insupercharging efficiency of the supercharger 9.

The first EGR cooler 24 is made adjacent to the exhaust purificationdevice 18 and the outer surface of the first EGR cooler 24 is fitted tothe outer surface of the downstream-side portion 34 of the exhaustpurification device 18 with the bracket 42 such that the gas flowdirection of the first EGR cooler 24 is opposite to the gas flowdirection of the downstream-side portion 34 of the exhaust purificationdevice 18 and that the central axis of the first EGR cooler 24 isdisposed along the longitudinal direction of the vehicle 100, therebyeliminating the need to fit the first EGR cooler 24 to the cylinderblock 6 of the engine 4 as in the conventional case. It is thus possibleto enhance the flexibility in placement of the first EGR cooler 24.Further, since the outer surface of the first EGR cooler 24 is fixed tothe outer surface of the downstream-side portion 34 of the exhaustpurification device 18 with the bracket 42, the first EGR cooler 24 andthe exhaust purification device 18 operate as one rigid body, which cansuppress generation of resonance between the first EGR cooler 24 and theexhaust purification device 18.

The EGR gas leading part 22 is disposed behind the downstream-sideportion 34 of the exhaust purification device 18 in the vehicle 100 andis disposed on the downstream side of the gas flow direction of theexhaust gas in the downstream-side portion 34, therefore, the exhaustgas flowing through the downstream-side portion 34 flows into the EGRgas leading part 22 without changing its direction. This can facilitatetaking the EGR gas out of the exhaust purification device 18. Therefore,for example, when the engine 2 is being operated in a low-revolutionlow-load range, the flow rate of the exhaust gas becomes small, but evenin such a case, a required flow rate of the exhaust gas can be ensured.

Since the EGR gas leading part 22 is disposed downstream of the exhaustpurification device 18, it is possible to take an exhaust gas passingthrough the exhaust purification device 18 and thus in an even lowertemperature state as the EGR gas, therefore it is possible to supply theEGR gas with an even lower temperature to the engine 2.

Since the second EGR gas flow outlet 50B of the second EGR cooler 26 islocated above the second EGR gas flow inlet 48B, when condensed water isgenerated in the second EGR cooler 26, the condensed water flowsupstream from the second EGR gas flow outlet 50B side to the second EGRgas flow inlet 48B side. Further, since the second EGR gas flow inlet48B is located above the first EGR gas flow outlet 40B of the first EGRcooler 24, the condensed water flows upstream to the first EGR cooler24.

Moreover, since the first EGR gas flow inlet 38B of the first EGR cooler24 is located below the first EGR gas flow outlet 40B, the condensedwater flowing from the second EGR cooler 26 and condensed watergenerated in the first EGR cooler 24 flow upstream from the first EGRgas flow outlet 40B side to the first EGR gas flow inlet 38B side. Sincethe first EGR gas flow inlet 38B is located above the exhaust outlet 18Aof the exhaust purification device 18, the condensed water flows towardthe exhaust outlet 18A of the exhaust purification device 18. As theexhaust outlet 18A is connected to the flexible pipe 20, the condensedwater is discharged to the outside through the flexible pipe 20.

With such a structure as described above, the condensed water generatedin the first EGR cooler 24 and the second EGR cooler 26 can bedischarged to the outside, thereby preventing suction of the condensedwater to the engine 2 side. Hence it is possible to prevent water hammerwhich may occur due to suction of condensed water. In addition, it ispossible to prevent accumulation of condensed water in the first EGRcooler 24, the second EGR cooler 26, and the first and second EGR pipes28, 30, and to prevent corrosion of these parts.

With respect to the exhaust purification device 18 disposed on the rearof the engine 2, the first EGR cooler 24 is disposed adjacent to theleft-side side surface of the exhaust purification device 18 in thevehicle-width direction, the first EGR pipe 28, the second EGR cooler26, and the second EGR pipe 30 are disposed along the left-side sidesurface of the engine 2 in the vehicle-width direction, and the secondEGR gas passage 30 communicates with the intake passage 11 at theposition of the EGR valve 10 on the front left side of the engine 2.Therefore, the EGR gas path leading from the exhaust purification device18 to the intake passage 11 through the first and second EGR coolers 24,26 can be disposed on the left side of the engine 2 in the vehicle-widthdirection where the EGR valve 10 is disposed. It is therefore possibleto make the EGR gas path short and the response of the EGR controlfavorable. Especially in the present embodiment, since the longitudinalaxis of the downstream-side portion 34 of the exhaust purificationdevice 18 is disposed on the left to the engine 2 in the vehicle-widthdirection, by disposing the EGR gas path which includes the first EGRcooler 24 and the second EGR cooler 26 along the left side of the engine2 in the vehicle-width direction, the EGR gas path can be made evenshorter.

Since the rear side ends of the exhaust purification device 18 and thefirst EGR cooler 24 overlap the floor tunnel region 114 as viewed frombelow and the side of the vehicle 100, even when the engine 2 and partsconnected thereto move rearward at the time of collision of the vehicle100, the exhaust purification device 18 and the first EGR cooler 24 areaccommodated in the floor tunnel region 144. It is therefore possible toensure the safety of vehicle passengers at the time of collision of thevehicle 100 and to prevent damage on the exhaust purification device 18and the first EGR cooler 24. Further, with this placement, it ispossible to dispose the exhaust purification device 18 and the first EGRcooler 24 such that the longitudinal axis follows the longitudinaldirection of the vehicle 100 on the rear of the engine 2, while ensuringthe safety of the vehicle passengers. Thus, the exhaust purificationdevice 18 and the first EGR cooler 24 can also be disposed along thelongitudinal direction as well as being disposed along the vehicle-widthdirection, thereby enhancing the flexibility in the placement directionof the exhaust purification device 18 and the first EGR cooler 24.

With the second EGR cooler 26 being provided downstream of the first EGRcooler 24, it is possible to ensure the required cooling capacity whilesuppressing increases in size of the first EGR cooler 24 and the secondEGR cooler 26. Since the increase in size of the first EGR cooler 24 canbe suppressed, it is possible to suppress the resonance between thefirst EGR cooler 24 and the exhaust purification device 18 to which thefirst EGR cooler 24 is fitted.

Since the first EGR pipe 28 is made up of the rubber hose, thevibrations of the first EGR cooler 24 and the second EGR cooler 26 canbe absorbed. This enables suppression of the resonance between the firstEGR cooler 24 and the second EGR cooler 26.

Second Embodiment

Next, a second embodiment of the present invention will be described. Inthe second embodiment, the turbo supercharger 62 is disposed behind theengine 2, and the EGR gas path leading from the exhaust purificationdevice 18 to the intake passage is different as compared to that in thefirst embodiment.

FIG. 7 is a side view of an intake and exhaust device 60 for a vehicleaccording to a second embodiment of the present invention. As shown inthis FIG. 7, the turbo supercharger 62 is disposed behind the engine 2and to the left of the center of the engine 2 in the vehicle-widthdirection. The turbo supercharger 62 includes a turbine (not shown)disposed on the right side and a compressor 62A disposed on the leftside. The turbine is connected to the exhaust manifold 12, and thecompressor 62A includes a compressor downstream passage 66 on thedownstream side. The compressor downstream passage 66 has one endconnected to the compressor 62A of the turbo supercharger 62, extends tothe left end of the engine 2 in the vehicle-width direction along thevehicle-width direction behind the engine 2, extends so as to beinclined downwardly toward the front side along the left-side sidesurface of the engine 2 in the vehicle-width direction, and is connectedto the intake manifold 8 on the front side of the engine 2. In thepresent embodiment, the passage from the compressor 62A of the turbosupercharger 62 to the intake manifold 8 through the compressordownstream passage 66 is an intake passage 68.

The exhaust purification device 18 is connected to the downstream sideof the turbine. The upstream-side end (exhaust gas inlet) of the exhaustpurification device 18 is disposed below the exhaust outlet of the turbosupercharger 62. The EGR gas leading part 22 and an EGR cooler 64 areconnected to the downstream side of the exhaust purification device 18.The structure of the EGR cooler 64 is the same as that of the first EGRcooler 24 of the first embodiment, and hence its description will beomitted here. The EGR cooler 64 is adjacent to the left side of theexhaust purification device 18 in the vehicle-width direction and hasthe outer surface fitted to the outer surface of the exhaustpurification device 18 with a bracket (not shown) as in the firstembodiment. The exhaust purification device 18 and the EGR cooler 64 areinclined downwardly toward the rear of the vehicle 100 as in the firstembodiment.

One end of an EGR cooler downstream passage 70 is connected to an EGRgas flow outlet 64A which is the downstream-side end of the EGR cooler64. The EGR cooler downstream passage 70 extends so as to be inclinedrearwardly along the longitudinal direction of the vehicle 100 on theleft sides of the exhaust purification device 18 and the turbosupercharger 64 in the vehicle-width direction. The other end of the EGRcooler downstream passage 70 is connected to a portion of the compressordownstream passage 66 which extends in the vehicle-width directionbehind the engine 2. An EGR valve 72 is provided in the middle of theEGR cooler downstream passage 70, and the EGR valve 72 is fixed to theturbo supercharger 62 with a bracket 74.

In an exhaust system device 60A with such a structure as in the firstembodiment, a part of the exhaust gas coming out of the exhaustpurification device 18 is taken out as the EGR gas by the EGR gasleading part 22 and cooled by the EGR cooler 64, and thereafter, the EGRgas is supplied to the compressor downstream passage 66 of the intakepassage 68 through the EGR cooler downstream passage 70.

The exhaust system device 60A of the second embodiment with such astructure as above achieves effects as follows other than similareffects to those in the first embodiment.

In the structure where the turbo supercharger 62 is provided behind theengine 2 and the compressor downstream passage 66 is provided on theleft side of the turbo supercharger 62 in the vehicle-width direction,the EGR cooler 64 is fitted to the left-side side surface of exhaustpurification device 18 in the vehicle-width direction while beingadjacent thereto, and the EGR cooler downstream passage 70 is alsodisposed on the left side of the exhaust purification device 18 in thevehicle-width direction. The EGR cooler downstream passage 70 is thenconnected to the portion of the compressor downstream passage 66 whichextends along the vehicle-width direction behind the engine 2. With sucha structure, both the EGR cooler 64 and the EGR cooler downstreampassage 70 are provided on the left side of the turbo supercharger 62 inthe vehicle-width direction where the compressor downstream passage 66is provided, namely, on the left side of the exhaust purification device18 in the vehicle-width direction, therefore, the EGR gas path leadingfrom the exhaust purification device 18 to the compressor downstreampassage 66 can be made short and the response of the EGR control can bemade favorable.

Further, by combination with the supercharger 9 shown in the firstembodiment, the supercharger 9 is driven at the time of the compressionself-ignition operation, and the turbo supercharger 62 is used toperform the supercharging at the time of the spark ignition operation,whereby the temperature of the exhaust gas is prevented from deviatingfrom the activation temperature range for the catalyst device at thetime of the compression self-ignition operation, and the exhaust gasenergy is consumed by the drive of the turbo supercharger at the time ofthe spark ignition operation, especially at the time of a high-loadoperation, so that it is possible to prevent the temperature of theexhaust gas from deviating from the activation temperature range for thecatalyst device.

Third Embodiment

Next, an intake and exhaust device 80 for a vehicle engine according toa third embodiment of the present invention will be described. In thethird embodiment, a description will be given for a structure in whichan exhaust purification device 82 of the intake and exhaust device 80for the vehicle engine according to the first embodiment is fixed to theengine 2. Further, the intake and exhaust device 80 according to thethird embodiment is different from the intake and exhaust device 1 ofthe first embodiment in the configuration of the EGR gas path leadingfrom the exhaust purification device 82 to the intake passage.

FIG. 8 is a perspective view of the intake and exhaust device 80 for thevehicle engine according to the third embodiment of the presentinvention. As shown in this FIG. 8, the exhaust purification device 82of the intake and exhaust device 80 for the vehicle engine according tothe third embodiment of the present invention is connected to theexhaust manifold 12 via an exhaust purification device introductionpassage 83 in the same manner as the exhaust purification device 18 ofthe first embodiment. In the present embodiment, as shown in FIG. 8, theexhaust purification device introduction passage 83 has a smallerdimension in the vehicle-width direction than the exhaust purificationdevice introduction passage 83 of the first embodiment and has asubstantially disk-like flat shape. A gas inlet 83A connected to themixing tube 16 of the exhaust manifold 12 is formed at the upper end ofthe exhaust purification device introduction passage 83, and a gasoutlet 83B for connection to the exhaust purification device 82 isformed on the left side of the exhaust purification device introductionpassage 83 in the vehicle-width direction.

The GPF is disposed in a downstream-side portion 84 of the exhaustpurification device 82, and this downstream-side portion 84 is a weightpart which accounts for most of the weight of the entire exhaustpurification device 82. The downstream-side portion 84 extends along thelongitudinal direction of the vehicle 100 as in the first embodiment.That is, the downstream-side portion 84 extends in the direction awayfrom the outer surface of the engine 2.

A radially projecting EGR leading part 85 is provided at the downstreamend (rear end) of the downstream-side portion 84 of the exhaustpurification device 82. An outlet (downstream end) 85A of the EGRleading part 85 is open to the front of the vehicle 100. An EGR pipe 86is connected to the outlet 85A, and this EGR pipe 86 extends along thelongitudinal direction of the vehicle 100 and has a downstream endconnected to an EGR cooler 87. In the present embodiment, only one EGRcooler 87 is provided, and this EGR cooler 87 is fixed to the sidesurface of the cylinder block 4 of the engine 2. Further, the EGR cooler87 has an upstream-side end connected to the EGR pipe 86 and adownstream-side end connected to the intake passage. In the presentembodiment, the EGR gas passage is formed including the EGR pipe 86 andthe EGR cooler 87.

FIG. 9 is a partial enlarged perspective view showing the installationstructure of the exhaust purification device 82 according to the thirdembodiment of the present invention, FIG. 10 is a side view of theintake and exhaust device 80 for the vehicle engine according to thethird embodiment of the present invention, and FIG. 11 is a partialenlarged sectional view showing the installation structure of theexhaust purification device 82 according to the third embodiment of thepresent invention.

Referring to aforementioned FIG. 8 and FIGS. 9 to 11, the exhaustpurification device 82 is fixed to outer surface of the engine 2 at theend of the downstream-side portion 84 on the engine side, namely, at theend thereof on the front side of the vehicle. More specifically, asshown in FIGS. 9 and 10, a boss 4A is formed on the outer surface of thecylinder block 4 of the engine 2, the boss 4A projecting rearwardly fromthe rear-side outer surface, and a first engine-side support bracket 88is fastened to this boss 4A with a bolt. The first engine-side supportbracket 88 is a plate-like member extending along the longitudinaldirection and the vertical direction of the vehicle 100 and has asmaller dimension in the vehicle-width direction than in thelongitudinal direction or the vertical direction.

Meanwhile, a first purifying device-side support bracket 90 connected tothe first engine-side support bracket 88 is provided at the end, on theleft side in the vehicle-width direction and front side of the vehicle,of the downstream-side portion 84 of the exhaust purification device 82.As illustrated in FIG. 11, the first purifying device-side supportbracket 90 is fixed to a container of the exhaust purification device 82by brazing, and projects from the outer surface of the upper part of theexhaust purification device 82 toward the left side in the vehicle-widthdirection. As illustrated in FIG. 11, the first purifying device-sidesupport bracket 90 extends slightly upward on the base end side fixed tothe outer surface of the exhaust purification device 82 and horizontallyextends on the tip side. The first purifying device-side support bracket90 is bolted to the first engine-side support bracket 88 on the tipside. Hence the exhaust purification device 82 is fixed to the outersurface of the engine 2.

FIG. 12 is a side view showing the installation structure of the exhaustpurification device according to the third embodiment of the presentinvention. FIG. 13 is a bottom view showing the installation structureof the exhaust purification device according to the third embodiment ofthe present invention. As shown in these FIGS. 12 and 13, the exhaustpurification device 82 is fixed to the outer surface of the cylinderblock 4 of the engine 2 also on the right-side side surface of thedownstream-side portion 84 in the vehicle-width direction. Morespecifically, the cylinder block 4 is formed with a plurality of bosses4B projecting rearwardly from the rear-side outer surface. A secondengine-side support bracket 92 is fixed to these bosses 4B. The secondengine-side support bracket 92 is a plate-like member extending alongthe longitudinal direction and the vertical direction of the vehicle 100and has a smaller dimension in the vehicle-width direction than in thelongitudinal direction or the vertical direction. Thus, the verticalrigidity of the second engine-side support bracket 92 is higher than therigidity thereof in the vehicle-width direction. A substantiallyL-shaped link bracket 93 is fixed to the tip side of the secondengine-side support bracket 92.

Meanwhile, a second purifying device-side support bracket 94 connectedto the second engine-side support bracket 92 via a link bracket 93 isfitted to the right-side side surface of the downstream-side portion 84of the exhaust purification device 82 in the vehicle-width direction.The second purifying device-side support bracket 94 is formed in asubstantially U-shape, and the tips of two tip portions 94B extendingboth sides of a base end portion 94A are fixed to the side surface ofthe downstream-side portion 84 of the exhaust purification device 82. Along hole 94C with its longitudinal axis disposed along thevehicle-width direction is formed on the base end portion 94A of thesecond purifying device-side support bracket 94. The second purifyingdevice-side support bracket 94 is fixed to the link bracket 93 throughthe long hole 94C with a bolt, to be supported by the second engine-sidesupport bracket 92.

Here, the second purifying device-side support bracket 94 is locatedbehind the first purifying device-side support bracket 90 in the vehicle100. The second purifying device-side support bracket 94 is supported bythe second engine-side support bracket 92 via the long hole 94C whilebeing supported by the outer surface of the engine 2, and hence theexhaust purification device 92 is supported so as to be movable in thevehicle-width direction.

The intake and exhaust device 80 for the vehicle engine with such astructure as above operates as follows.

During the operations of the vehicle engine 2 and the intake and exhaustdevice 80, the downstream-side portion 84 of the exhaust purificationdevice 82, which is the weight part, extends in the direction fartheraway from the outer surface of the engine 2 than the first purifyingdevice-side support bracket 90, more specifically, extends along thelongitudinal direction of the vehicle 100, therefore, the exhaustpurification device 82 vibrates to function as a dynamic damper. Thiscancels out the vibration of the engine 2.

At the time of using the downstream-side portion 84 as the dynamicdamper, the exhaust purification device introduction passage 83functions as a spring of the dynamic damper. Further, the support partformed by the first engine-side support bracket 88 and the firstpurification device-side support bracket functions as a part foradjusting a spring constant of the dynamic damper while allowinghorizontal variation of the downstream-side portion 84. Meanwhile, thesupport part formed by the second engine-side support bracket 92, thelink bracket 93, and the second purifying device-side support bracket 94functions so as to suppress vertical vibration of the downstream-sideportion 84 while allowing horizontal vibration thereof.

The intake and exhaust device 80 for the vehicle engine with such astructure achieves effects as follows.

The exhaust purification device 82 is supported on the outer surface ofthe engine 2 by the first engine-side support bracket 88 and the firstpurifying device-side support bracket 90 and the downstream-side portion84 being the weight part of the exhaust purification device 82 isdisposed extending behind in the direction away from the outer surfaceof the engine 2 than the position supported by these support brackets88, 90, therefore, the exhaust purification device 82 vibrates tofunction as the dynamic damper during the operation of the engine 2. Asa result, it is possible to cancel out the vibration of the engine 2 bythe vibration of the exhaust purification device 82, and reduce thevibration and noise of the vehicle 100.

The present invention is not limited to the above embodiments and may,for example, be in such a form as follows.

The longitudinal axis of the first EGR cooler 24 or the EGR cooler 64may be substantially parallel to the central axis of the downstream-sideportion 34 of the exhaust purification device. For example, in the sideview of the vehicle, the longitudinal axis of the EGR cooler and thecentral axis of the downstream-side end of the exhaust purificationdevice may not necessarily match or be parallel to each other but mayintersect with each other. In short, the longitudinal axis of the EGRcooler may be disposed along the longitudinal direction of the vehicle.

In the above embodiments, both the first EGR cooler 24 and the secondEGR cooler 26 are of the water-cooling types, but this is notrestrictive, and when two EGR coolers are provided in series, theupstream-side EGR cooler may be of an air-cooling type while thedownstream-side EGR cooler may be of a water-cooling type. Employing theair-cooling type as the EGR cooler enables prevention of the increase insize of the EGR cooler as compared to the water-cooling type. Further,the EGR gas can be roughly cooled by the upstream-side air-cooling typeEGR cooler and can then be reliably cooled down to a desired temperatureby the downstream-side water-cooling type EGR cooler, thus enablingefficient cooling of the EGR gas.

Moreover, in the above embodiments, the cooling-water circuits of thefirst EGR cooler 24 and the second EGR cooler 26 are coupled in series,but this is not restrictive, and each of the first EGR cooler and thesecond EGR cooler may be provided on a different cooling-water circuitso as to have different cooling performance.

In the above embodiments, the engine performs the compressionself-ignition operation, but the present invention is not restrictedthereto, and it may be configured such that the spark ignition operationcan be conducted concurrently with the compression self-ignitionoperation.

In the above embodiments, the engine performs lean-burn, but this is notrestrictive, and any air fuel ratio for burning can be selected.

In the above embodiments, the supercharger has been used which isbelt-driven by a force generated by burning of the engine, but this isnot restrictive, and it is possible to employ any type of superchargerdriven by a force other than the exhaust gas, such as an electricsupercharger driven by electric power of a motor or the like.

In the above embodiments, in the exhaust purification device, the weightpart, namely the GPF being the downstream-side portion 34 is disposed soas to extend along the longitudinal direction of the vehicle 100, butthis is not restrictive, and for example, the exhaust purificationdevice may be disposed so as to extend along the vertical direction ofthe vehicle.

LIST OF REFERENCE NUMERALS

-   1, 60 intake and exhaust device-   1A, 60A exhaust system device-   2 engine-   11 intake passage-   18 exhaust purification device-   22 EGR gas leading part-   24 first EGR cooler-   26 second EGR cooler-   28 first EGR pipe-   30 second EGR pipe-   32 upstream-side portion-   34 downstream-side portion-   100 vehicle

1. An intake and exhaust device for a vehicle engine which is capable toperform a compression self-ignition operation, the device comprising onan intake passage a supercharger driven by a force other than an exhaustgas, wherein an exhaust purification device disposed on an exhaustpassage is disposed adjacent to an outer surface of the engine.
 2. Theintake and exhaust device for the vehicle engine according to claim 1,wherein the supercharger is a supercharger driven by an output shaft ofthe engine.
 3. The intake and exhaust device for the vehicle engineaccording to claim 1, wherein the supercharger is an electricsupercharger.
 4. The intake and exhaust device for the vehicle engineaccording to claim 2, wherein the intake and exhaust device is capableto perform a spark ignition operation, a turbo supercharger is providedupstream of the exhaust purification device on the exhaust passage,supercharging is performed by the turbo supercharger when the sparkignition operation is conducted, and supercharging is performed by thesupercharger when the compression self-ignition operation is conducted.5. The intake and exhaust device for the vehicle engine according toclaim 3, wherein the intake and exhaust device is capable to perform aspark ignition operation, a turbo supercharger is provided upstream ofthe exhaust purification device on the exhaust passage, supercharging isperformed by the turbo supercharger when the spark ignition operation isconducted, and supercharging is performed by the electric superchargerwhen the compression self-ignition operation is conducted.
 6. The intakeand exhaust device for the vehicle engine according to claim 1, whereinthe engine has an intake system disposed on a vehicle-front side and anexhaust system disposed on a vehicle-rear side, and the supercharger isdisposed on the vehicle-front side of the engine.
 7. The intake andexhaust device for the vehicle engine according to claim 1, wherein theexhaust purification device includes a particulate filter part and anexhaust gas recirculation (EGR) gas leading part provided downstream ofthe particulate filter part, and the EGR gas leading part is connectedto an upstream of the supercharger via an EGR gas passage.
 8. The intakeand exhaust device for the vehicle engine according to claim 1, whereinthe exhaust purification device is supported on the outer surface of theengine by a support part, and a weight part of the exhaust purificationdevice is disposed extending in a direction away from the outer surfacethan the support part.